1. Field of the Invention
This invention relates to a new compound, 3-O-(.beta.-D-glucuronopyranosyl)-soyasapogenol B, and salts thereof as well as to a process for preparing the same.
The compounds of this invention have anticomplementary activity and are useful as therapeutic agents for autoimmune diseases, collagen diseases, and rheumatic diseases.
2. Description of the Prior Art
Various compounds related to the compound of this invention are known. For example, glycyrrhizin (Yasuhiro Ariga, Hiroyuki Sumi, Yumiko Takada and Akikazu Takada, Abridgements of Lecture Programs on Seminar of the Plasmin Research Association, page 65 (1977); Koretsugu Arimoto, Kaneyuki Mineta, Hiroyuki Sumi, Yumiko Takada and Akikazu Takada, Proceedings of the 14th Symposium on Complements, p. 79-82 (1977)); and 3-O-(6-O-methyl-.beta.-D-glucuronopyranosyl)-soyasapogenol B (Isao Kitagawa, Masayuki Yoshikawa and Ichiro Yoshioka, Chem. Pharm. Bull., 22, p. 1339 (1974); Ibid., 24, p. 121 (1976)), etc., are known. The former compound has a steroid like structure and exhibits an activity similar to that of steroids. For example, it shows an inhibitory activity against plasmin, urokinase, Kallikrein, thrombin and complements. On the other hand, the physiological activities of the latter have not yet been reported. In contrast, the compound of this invention and salts thereof have an anticomplementary activity which is unexpectedly superior to that of glycyrrhizin and which is quite unexpected from 3-O-(6-O-methyl-.beta.-D-glucuronopyranosyl)-soyasapogenol B as will be apparent from the results of pharmacological tests described hereinafter.